1. Field of the Invention
The invention relates to keyboards, and more particularly to keyboards providing enhanced operational sensitivity.
2. Description of the Related Art
A conventional key structure of a remote control comprises a keycap, a conductive elastomer, a switch (such as an edge connector), and a printed circuit board. The switch is disposed on the printed circuit board. The conductive elastomer is connected to the keycap and corresponds to the switch. An operator can press the keycap, forcing the conductive elastomer connected thereto to compress the switch. The switch is thus activated and outputs a corresponding signal.
Nevertheless, the conventional key structure has many drawbacks. To effectively activate the switch, the operator must press the center of the keycap. Specifically, when the operator presses corners of the keycap, the conductive elastomer often cannot compress the switch, causing ineffective operation of the key structure. Moreover, due to manufacturing considerations, the conventional key structure cannot provide waterproof and dustproof functions. Furthermore, the conductive elastomer often contains silicon oil. After long-term use, the conductive elastomer is easily broken and the silicon oil leaks from the interior thereof, causing damage to the entire key structure. Additionally, the conductive elastomer is expensive, such that the manufacturing costs of the key structure cannot be reduced.
Moreover, referring to FIG. 4, a conventional key structure 1 comprises a circuit board 10 and a key assembly 20. The key assembly 20 comprises multiple keys 21 and multiple protrusions 22. Each protrusion 22 corresponds to each key 21 and is disposed thereunder. When one of the keys 21 is pressed, the protrusion 22 disposed thereunder compresses the circuit board 10, outputting a corresponding signal.
Nevertheless, as the entire key assembly 20 often comprises soft material, power or kinetic energy from pressing the key 21 is offset by deformation of the key assembly 20. Displacement of the corresponding protrusion 22 is insufficient and thus the protrusion 22 cannot exactly compress the circuit board 10. Accordingly, the key 21 must be pressed again to function, causing inconvenience of operation. The aforementioned problem is particularly obvious with a multiple key.
Hence, there is a need for a keyboard providing soft tactile sensitivity for the operator and appropriate rigidity for efficient operation.